THIS INVENTION concerns an overhead lighting appliance of the type known as a luminaire and consisting essentially of one or more horizontally disposed lamp tubes housed within a generally arcuately diverging longitudinal reflector assembly with crossblades at spaced disposition along the reflector assembly and extending at right angles to the longitudinal axis of the fluorescent lamp tube.
The purpose of the crossblades, in addition to assisting reflection of the light outwardly of the appliance, is to remove glare from the appliance by obscuring a direct line of sight to the lamp tube beyond a certain position beneath the appliance.
Whilst avoiding glare by the provision of such crossblades it is essential also to ensure, as far as possible, that the light output from the lamp tube is not excessively impaired or reduced by the presence of the crossblades between the tube and the light emission aperture or window of the appliance.
Typically, such crossblades are inwardly curved and tapered downwardly in cross-section, each terminating in a narrow line at its base which extends transversely across the appliance. At its upper end, each crossblade must have a thickness adequate to prevent direct reflection from the lamp tube thus to avoid glare and it is an object of the present invention to provide a crossblade design as a compromise between minimising glare and preventing, as far as possible, any appreciable loss of light output.
According to the present invention, an overhead lighting appliance having at least one longitudinally extending and horizontally disposed lamp tube housed in an upper region of a reflector assembly of generally arcuate downwardly diverging form, including longitudinally spaced cross blades extending transversely across the reflector housing; characterised in that each cross blade includes opposed outer and upper regions of reduced cross section extending outwardly from respective inclined planes which lie along the appliance and extend upwardly from adjacent outer lowermost corner regions respectively of the cross blade and form tangents to an upper semi-circle concentric with the longitudinal axis of the lamp tube.